Prostaglandin E2 production by Candida albicans and Candida dubliniensis

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Date
2011-11
Authors
Ells, Ruan
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University of the Free State
Abstract
English: Arachidonic acid (AA) [20:4(n-6)] is released from infected host cells during Candida albicans infection and may serve as carbon source for yeast growth and as precursor for the production of biologically active eicosanoids, such as prostaglandin E2 (PGE2) by C. albicans. Prostaglandin E2 is an important virulence factor in C. albicans and involved in biofilm formation. Biofilms increase damage in host cells and are more resistant to antifungal drugs than planktonic yeast cells. This study evaluated the production of prostaglandins, PGE2 and PGF2α, by biofilms of C. albicans and the closely related C. dubliniensis. Since, the mechanism involved in this production is still unclear, it was of interest to investigate the effect of different AA metabolism inhibitors on PGE2 production by biofilms of these Candida species. The experiments were done by growing Candida biofilms in the presence of AA as well as cytochrome P450 (CYP450), multicopper oxidase, cyclooxygenase (COX) and lipoxygenase (LOX) inhibitors. The PGE2 and PGF2α concentrations were determined by a monoclonal enzyme-linked immunosorbent assay (ELISA) and verified with LCMS/MS. The results obtained indicate the ability of C. albicans and C. dubliniensis biofilms to produce PGE2 and PGF2α, from exogenous AA. The use of different inhibitors suggested that CYP450s and multicopper oxidases are involved in PGE2 production by these Candida biofilms.
Afrikaans: Arachidonic acid (AA) [20:4(n-6)] is released from infected host cells during Candida albicans infection and may serve as carbon source for yeast growth and as precursor for the production of biologically active eicosanoids, such as prostaglandin E2 (PGE2) by C. albicans. Prostaglandin E2 is an important virulence factor in C. albicans and involved in biofilm formation. Biofilms increase damage in host cells and are more resistant to antifungal drugs than planktonic yeast cells. This study evaluated the production of prostaglandins, PGE2 and PGF2α, by biofilms of C. albicans and the closely related C. dubliniensis. Since, the mechanism involved in this production is still unclear, it was of interest to investigate the effect of different AA metabolism inhibitors on PGE2 production by biofilms of these Candida species. The experiments were done by growing Candida biofilms in the presence of AA as well as cytochrome P450 (CYP450), multicopper oxidase, cyclooxygenase (COX) and lipoxygenase (LOX) inhibitors. The PGE2 and PGF2α concentrations were determined by a monoclonal enzyme-linked immunosorbent assay (ELISA) and verified with LCMS/MS. The results obtained indicate the ability of C. albicans and C. dubliniensis biofilms to produce PGE2 and PGF2α, from exogenous AA. The use of different inhibitors suggested that CYP450s and multicopper oxidases are involved in PGE2 production by these Candida biofilms. Meeste van wat bekend is oor die biologie en die funksie van oksilipiene, suurstofryke poli-onversadigde vetsure en metaboliete, insluitende die eikosanoïede soos prostaglandiene, kom vanuit die studie van soogdierbiologie. Hierdie verbindings is alomteenwoordig in die natuur en kom voor in alle eukariotiese organismes, insluitende fungi. Dit is ook in hierdie groep organismes wat die minste bekend is oor die metaboliese bane wat lei tot die produksie van oksilipiene, insluitend die afgelei van arachidoonsuur (AA) (n-6 vetsuur), en die funksies van hierdie verbindings in die biologie van fungi en giste. Candida spesies het die vermoë om pro-inflammatoriese eikosanoïede, soos prostaglandien E2 (PGE2), te produseer vanaf AA wat deur die gasheer vrygestel word. Candida albicans is 'n belangrike opportunistiese patogeen wat sistemiese infeksies in mense veroorsaak. ‘n Belangrike virulensiefaktor in C. albicans is die vermoë om pro-inflammatoriese PGE2, wat biofilm vorming verhoog en die gasheer se immuunstelsel beinvloed, te produseer. Biofilms verhoog die skade aan gasheerselle en is meer bestand teen antifungale middels as planktoniese gisselle. Dit is 'n belangrike navorsingsveld wat kan bydra tot die begrip van die komplekse interaksies tussen gasheer en patogeen en wat kan lei tot die identifisering van nuwe antifungale middels of teikens. Hierdie studie het die produksie van die prostaglandiene, PGE2 en PGF2α, vanaf eksterne AA, deur biofilms van C. albicans en die nabyverwante gisspesies, C. dubliniensis, sowel as die effek van verskillende AA metabolisme inhibeerders op PGE2 produksie bepaal. Candida albicans en C. dubliniensis biofilms was albei in staat om PGE2 en PGF2α vanaf eksterne AA te vervaardig. Die gebruik van verskillende inhibeerders het aangedui dat sitochroom P450s en multikoperoksidases betrokke is in PGE2 produksie deur hierdie Candida biofilms. Dit is bekend dat soogdierselle nie PGE2 kan produseer vanaf nie-metiel onderbreekte vetsure, soos skiadoonsuur (SA) (n-6 vetsuur) nie. Hierdie eienskap verleen aan hierdie vetsure moontlike antiinflammatoriese aktiwiteite. Hierdie studie het die inkorporasie van SA in die lipiede van epiteelselle aangedui. Dit het PGE2 produksie verminder en sitokienprofiele beïnvloed in epiteelselle wat SA geЇnkorporeer het en geЇnfekteer is met C. albicans of C. dubliniensis. Dit dui daarop dat die inkorporering van n-6 nie-metiel onderbreekte vetsure, soos SA, kan lei tot 'n afname in die pro-inflammatoriese prostaglandiene, veral PGE2, wat tot voordeel van die gasheer tydens 'n Candida.infeksie kan wees. Interessant genoeg was beide C. albicans en C. dubliniensis biofilms nie in staat om PGE2 te produseer vanaf eksterne SA nie. Verdere genomiese hibridiseringstudies is gebruik om die regulering van C. albicans biofilm gene tydens inkubasie in die teenwoordigheid van eksterne AA en SA te evalueer. Transkripsionele analise het aangedui dat die gene wat differensieël uitgedruk is in die teenwoordigheid van AA uiteenlopende funksies het wat nie normaalweg vereis word vir selgroei nie. Gene wat kodeer vir oksidoreduktase en hidrolase aktiwiteit was gereguleer, maar is nie duidelik betrokke by PGE2 produksie nie. Interessant genoeg, gene wat kodeer vir ABC-transporters, asook gene wat betrokke is by filamentagtige en hifese groei, koolhidraat metaboliese prosesse en oksidatiewe stres reaksie, is differensieël uitgedruk in die teenwoordigheid van AA. Verdere studie van hierdie differensieël uitgedrukte gene is nodig om te evalueer hoe hulle betrokke mag wees in AA metabolisme en PGE2 produksie.
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Keywords
Biofilms, Candida albicans, Candida dubliniensis, Eicosanoids, ELISA, Hep2C, Non-methylene interrupted fatty acids, Oxidoreductases, Polyunsaturated, Prostaglandins, Antifungal agents, Thesis (Ph.D. (Microbial, Biochemical and Food Biotechnology))--University of the Free State, 2011
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